Photoactive additives containing siloxane

ABSTRACT

Photoactive additives are disclosed. Such additives are polymers or oligomers that contain UV-active groups (such as ketone groups) and contain polysiloxane blocks as well. When added to a base polymeric resin and used in molding, this structure promotes migration of the additive to the surface. Crosslinking occurs upon exposure to ultraviolet light.

This application claims priority to U.S. Provisional Patent Application Ser. No. 61/789,243, filed Mar. 15, 2013. The disclosure of that application is hereby fully incorporated by reference herein.

BACKGROUND

The present disclosure relates to photoactive additives containing a photoactive group and polysiloxane blocks. These additives can be used for crosslinking polymers. More particularly, it is believed that these additives will preferentially migrate to the surface of articles formed therefrom, enhancing the crosslinking effect. Also included are compositions including such additives, as well as products (e.g. molded articles, sheets, films, etc.) formed from such methods and compositions.

Polycarbonates (PC) are synthetic engineering thermoplastic resins, and are a useful class of polymers having many beneficial properties. Polycarbonate resins are both strong and transparent, and are used for a number of different commercial applications, including electronic engineering (E&E) parts, mechanical parts, etc.

Polycarbonate polymers/resins and blends containing polycarbonate polymers exhibit flame retardance properties. However, such polymers drip when exposed to a flame, and this behavior worsens as the wall thickness decreases. This behavior greatly diminishes their use in transparent and opaque thin wall applications where a V0 or 5VA flame retardance rating is required. These polymers also have relatively poor chemical resistance. It would be desirable to provide additives that can improve these properties.

BRIEF DESCRIPTION

The present disclosure is directed to additives that contain photoactive groups and polysiloxane blocks. The additives are formed by the reaction of at least a first photoactive moiety with a first linker moiety and a polysiloxane monomer. Generally, carbonate or ester linkages are found in the additives. The additives can be used to crosslink resins and improve their flame resistance and/or chemical resistance.

Additionally, the present disclosure is directed to processes of improving characteristics, such as chemical or flame resistance, of a resin or composition, and/or articles formed therefrom, by promoting migration of ultraviolet light active oligomers/polymers to the surface. For example, in one non-limiting embodiment, the disclosure relates to a method of promoting migration of a photoactive additive to the surface of a molded article by incorporating a polysiloxane monomer in the photoactive additive. The molded article is then subsequently cross-linked with light of a certain wavelength, such as ultraviolet light, producing an article with enhanced characteristics.

Disclosed in several embodiments herein are photoactive additives that are a cross-linkable polycarbonate terpolymer formed from a reaction comprising: a dihydroxybenzophenone; a first linker moiety comprising a plurality of functional groups, wherein each functional group reacts with the hydroxyl groups of the dihydroxybenzophenone; a diol chain extender; an end-capping agent; and a polysiloxane monomer in an amount such that the additive contains from 1 wt % to 25 wt % of siloxane, based on the total weight of the polycarbonate terpolymer.

In particular specific embodiments, the dihydroxybenzophenone is 4,4′-dihydroxybenzophenone; the diol chain extender is bisphenol-A; and the first linker moiety is phosgene.

The additive may contain from about 0.5 mole % to about 50 mole % of the dihydroxybenzophenone. Alternatively, the additive may contain from about 1 wt % to about 25 wt % of the dihydroxybenzophenone.

The end-capping agent can be selected from the group consisting of phenol, p-t-butylphenol, p-cumylphenol, octylphenol, p-cyanophenol, and a monohydroxybenzophenone.

The polysiloxane monomer may have the structure of one of Formulas (I)-(III), as defined further herein. The diol chain extender may have the structure of one of Formulas (A)-(G), as defined further herein. The first linker moiety may have the structure of one of Formulas (30), (32), or (33), as defined further herein.

The additive of claim 1, wherein the molar ratio of the dihydroxybenzophenone to the first linker moiety may be from 1:2 to 1:200.

The reaction that forms the photoactive additive can further comprise a secondary linker moiety having at least three functional groups, each of which can react with a functional group of the first linker moiety. The secondary linker moiety can have the structure of one of Formulas (43)-(48), as defined further herein.

The additive can have a weight average molecular weight of 15,000 or greater. In particular embodiments, the cross-linkable polycarbonate terpolymer has a weight-average molecular weight from 17,000 to 80,000 Daltons, as measured by gel permeation chromatography using a UV-VIS detector and polycarbonate standards.

In many embodiments, a molded part formed from the cross-linkable polycarbonate terpolymer exhibits 100% ductility at minus 20° C. at 3.2 mm thickness in a notched Izod test according to ASTM D256.

Also disclosed are products formed from a composition comprising the photoactive additive of claim 1. The product can be a molded article, a film, a sheet, a layer of a multilayer film, or a layer of a multilayer sheet. The product may be formed by injection molding, overmolding, co-injection molding, extrusion, multilayer extrusion, rotational molding, blow molding, or thermoforming. In particular embodiments, the product is exposed to UV radiation to cause crosslinking of the photoactive additive.

Also disclosed are blends comprising the additive of claim 1 and a polymeric base resin that is different from the photoactive additive.

Also disclosed are processes for making a photoactive additive from a dihydroxybenzophenone, a diol chain extender, a polysiloxane monomer, an end-capping agent, a carbonate precursor, a base, a tertiary amine catalyst, water, and a water-immiscible organic solvent, comprising: pre-reacting the polysiloxane monomer with the carbonate precursor in a tubular reactor to form chloroformates; combining the dihydroxybenzophenone, diol chain extender, tertiary amine catalyst, water, and water-immiscible solvent to form a reaction mixture; adding the carbonate precursor to the reaction mixture over a first time period while co-adding the base to regulate the reaction pH; adding the end-capping agent and the chloroformates to the reaction mixture for a second time period while continuing to add the carbonate precursor and the base; and continuing to add the carbonate precursor and the base to the reaction mixture for a third time period after the second time period is complete to obtain the photoactive additive; wherein the polysiloxane monomer is present in an amount such that the additive contains from 1 wt % to 25 wt % of siloxane, based on the total weight of the polycarbonate resin.

In particular embodiments, the carbonate precursor is phosgene, the diol chain extender is bisphenol-A, the base is an alkali metal hydroxide, and the water-immiscible organic solvent is methylene chloride.

The end-capping agent can be dissolved in a solvent prior to being added to the reaction mixture, the solvent being either the water-immiscible organic solvent or water containing a base. More specifically, the end-capping agent cane be dissolved in a dilute aqueous sodium hydroxide solution. In specific embodiments, the solution contains from about 1 to about 2 moles of NaOH per mole of the end-capping agent, and contains from about 5 wt % to about 20 wt % of the end-capping agent compound.

The reaction pH is generally regulated to remain between about 8.5 and about 10.

Also disclosed herein is a cross-linkable polycarbonate terpolymer formed from a reaction comprising a dihydroxybenzophenone, a diol chain extender, and a polysiloxane monomer in an amount such that the terpolymer contains from 1 wt % to 25 wt % of siloxane, based on the total weight of the terpolymer, wherein the terpolymer is formed by: pre-reacting the polysiloxane monomer with a carbonate precursor in a tubular reactor to form chloroformates; combining the dihydroxybenzophenone, the diol chain extender, a tertiary amine catalyst, water, and a water-immiscible solvent to form a reaction mixture; adding the carbonate precursor to the reaction mixture over a first time period while co-adding the base to regulate the reaction pH; adding the chloroformates to the reaction mixture for a second time period while continuing to add the carbonate precursor and the base; continuing to add the carbonate precursor and the base to the reaction mixture for a third time period after the second time period is complete to obtain the terpolymer.

Additionally disclosed herein are crosslinked layers formed from a polymeric blend that has been exposed to UV radiation, the blend comprising: (a) a photoactive additive that is a cross-linkable polycarbonate terpolymer formed from a reaction comprising a dihydroxybenzophenone, a diol chain extender, and a polysiloxane monomer in an amount such that the terpolymer contains from 1 wt % to 25 wt % of siloxane, based on the total weight of the terpolymer; and (b) a polymer resin which is different from the photoactive additive. The crosslinked layer usually contains chains from both the photoactive additive and the polymer resin. The crosslinking can be sufficient to create a continuous insoluble layer containing both the photoactive additive and the polymer resin.

These and other non-limiting characteristics are more particularly described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a brief description of the drawings, which are presented for the purposes of illustrating the exemplary embodiments disclosed herein and not for the purposes of limiting the same.

FIG. 1 illustrates the formation of a photoactive additive (oligomer/polymer) from a difunctional photoactive moiety, a first linker moiety, a chain extender, an end-capping agent, and a polysiloxane monomer.

FIG. 2 illustrates the formation of a photoactive additive (oligomer/polymer) from a monofunctional photoactive moiety that acts as an endcap, a polysiloxane monomer, a diol chain extender, and a first linker moiety.

FIG. 3 illustrates the crosslinking mechanism of the photoactive additive.

DETAILED DESCRIPTION

The present disclosure may be understood more readily by reference to the following detailed description of desired embodiments and the examples included therein. In the following specification and the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings.

DEFINITIONS

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present invention. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

As used in the specification and in the claims, the term “comprising” may include the embodiments “consisting of” and “consisting essentially of.” The terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that require the presence of the named ingredients/steps and permit the presence of other ingredients/steps. However, such description should be construed as also describing compositions or processes as “consisting of” and “consisting essentially of” the enumerated ingredients/steps, which allows the presence of only the named ingredients/steps, along with any impurities that might result therefrom, and excludes other ingredients/steps.

Numerical values in the specification and claims of this application, particularly as they relate to polymers or polymer compositions, reflect average values for a composition that may contain individual polymers of different characteristics. Furthermore, unless indicated to the contrary, the numerical values should be understood to include numerical values which are the same when reduced to the same number of significant figures and numerical values which differ from the stated value by less than the experimental error of conventional measurement technique of the type described in the present application to determine the value.

All ranges disclosed herein are inclusive of the recited endpoint and independently combinable (for example, the range of “from 2 grams to 10 grams” is inclusive of the endpoints, 2 grams and 10 grams, and all the intermediate values). The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value; they are sufficiently imprecise to include values approximating these ranges and/or values.

As used herein, approximating language may be applied to modify any quantitative representation that may vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about” and “substantially,” may not be limited to the precise value specified, in some cases. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. The modifier “about” should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression “from about 2 to about 4” also discloses the range “from 2 to 4.” The term “about” may refer to plus or minus 10% of the indicated number. For example, “about 10%” may indicate a range of 9% to 11%, and “about 1” may mean from 0.9-1.1. Other meanings of “about” may be apparent from the context, such as rounding off, so, for example “about 1” may also mean from 0.5 to 1.4.

For the recitation of numeric ranges herein, each intervening number there between with the same degree of precision is explicitly contemplated. For example, for the range of 6-9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0-7.0, the number 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are explicitly contemplated.

Compounds are described using standard nomenclature. For example, any position not substituted by any indicated group is understood to have its valency filled by a bond as indicated, or a hydrogen atom. A dash (“-”) that is not between two letters or symbols is used to indicate a point of attachment for a substituent. For example, the aldehyde group —CHO is attached through the carbon of the carbonyl group.

The term “aliphatic” refers to a linear or branched array of atoms that is not aromatic. The backbone of an aliphatic group is composed exclusively of carbon. The aliphatic group may be substituted or unsubstituted. Exemplary aliphatic groups include, but are not limited to, methyl, ethyl, isopropyl, hexyl, and cyclohexyl.

The term “aromatic” refers to a radical having a ring system containing a delocalized conjugated pi system with a number of pi-electrons that obeys Hückel's Rule. The ring system may include heteroatoms such as nitrogen, sulfur, selenium, silicon and oxygen, or may be composed exclusively of carbon and hydrogen. Aromatic groups are not substituted. Exemplary aromatic groups include, but are not limited to, phenyl, pyridyl, furanyl, thienyl, naphthyl and biphenyl.

The term “ester” refers to a radical of the formula —CO—O—, wherein the carbon atom and the oxygen atom are both covalently bonded to carbon atoms.

The term “carbonate” refers to a radical of the formula —O—CO—O—, wherein the oxygen atoms are both covalently bonded to carbon atoms. Note that a carbonate group is not an ester group, and an ester group is not a carbonate group.

The term “hydroxyl” refers to a radical of the formula —OH, wherein the oxygen atom is covalently bonded to a carbon atom.

The terms “carboxy” or “carboxyl” refer to a radical of the formula —COOH, wherein the carbon atom is covalently bonded to another carbon atom. It should be noted that for the purposes of this disclosure, a carboxyl group may be considered as having a hydroxyl group. However, it should be noted that a carboxyl group can participate in certain reactions differently from a hydroxyl group.

The term “alkyl” refers to a radical composed entirely of carbon atoms and hydrogen atoms which is fully saturated. The alkyl radical may be linear, branched, or cyclic.

The term “aryl” refers to an aromatic radical that is composed exclusively of carbon and hydrogen. Exemplary aryl groups include phenyl, naphthyl, and biphenyl. Note that “aryl” is a subset of aromatic.

The term “heteroaryl” refers to an aromatic radical having a ring system that is composed of carbon, hydrogen, and at least one heteroatom. Exemplary heteroaryl groups include pyridyl, furanyl, and thienyl. Note that “heteroaryl” is a subset of aromatic, and is exclusive of “aryl”.

The term “halogen” refers to fluorine, chlorine, bromine, and iodine.

The term “alkoxy” refers to an alkyl radical which is attached to an oxygen atom, i.e. —O—C_(n)H_(2n+1).

The term “aryloxy” refers to an aryl radical which is attached to an oxygen atom, e.g. —O—C₆H₅.

The term “hydrocarbon” refers to a radical which is composed exclusively of carbon and hydrogen. Both alkyl and aryl groups are considered hydrocarbon groups.

The term “alkenyl” refers to a radical composed entirely of carbon atoms and hydrogen atoms which contains at least one carbon-carbon double bond that is not part of an aryl or heteroaryl structure. The alkenyl radical may be linear, branched, or cyclic. An exemplary alkenyl radical is vinyl (—CH═CH₂).

The term “alkenyloxy” refers to an alkenyl radical which is attached to an oxygen atom, e.g. —O—CH═CH₂.

The term “arylalkyl” refers to an aryl radical which is attached to an alkyl radical, e.g. benzyl (—CH₂—C₆H₅).

The term “alkylaryl” refers to an alkyl radical which is attached to an aryl radical, e.g. tolyl (—C₆H₄—CH₃).

The term “nitro” refers to a radical of the formula —NO₂.

The term “cyano” refers to a radical of the formula —C≡N.

The term “copolymer” refers to a polymer derived from two or more structural unit or monomeric species, as opposed to a homopolymer, which is derived from only one structural unit or monomer.

The terms “Glass Transition Temperature” or “Tg” refer to the maximum temperature that a polymer, such as a polycarbonate, will have one or more useful properties. These properties include impact resistance, stiffness, strength, and shape retention. The Tg of a polycarbonate therefore may be an indicator of its useful upper temperature limit, particularly in plastics applications. The Tg may be measured using a differential scanning calorimetry method and expressed in degrees Celsius. The glass transition temperatures (Tg) described herein are measures of heat resistance of, for example, polycarbonate and polycarbonate blends. The Tg can be determined by differential scanning calorimetry, for example by using a TA Instruments Q1000 instrument, for example, with setting of 20° C./min ramp rate and 40° C. start temperature and 200° C. end temperature.

The term “halo” means that the substituent to which the prefix is attached is substituted with one or more independently selected halogen radicals. For example, “C₁-C₆ haloalkyl” means a C₁-C₆ alkyl substituent wherein one or more hydrogen atoms are replaced with independently selected halogen radicals. Non-limiting examples of C₁-C₆ haloalkyl include chloromethyl, 1-bromoethyl, fluoromethyl, difluoromethyl, trifluoromethyl, and 1,1,1-trifluoroethyl. It should be recognized that if a substituent is substituted by more than one halogen radical, those halogen radicals may be identical or different (unless otherwise stated).

The term “haze” refers to the percentage of transmitted light, which in passing through a specimen deviates from the incident beam by forward scattering. Percent (%) haze may be measured according to ASTM D 1003-07.

The term “Melt Volume Rate” (MVR) or “Melt Flow Rate (MFR)” refers to the flow rate of a polymer in a melt phase as determined using the method of ASTM D1238-10. The MVR of a molten polymer is measured by determining the amount of polymer that flows through a capillary of a specific temperature over a specified time using standard weights at a fixed temperature. MVR is expressed in cubic centimeter per 10 minutes, and MFR is expressed in grams per 10 minutes. The higher the MVR or MFR value of a polymer at a specific temperature, the greater the flow of that polymer at that specific temperature.

The term “Percent transmission” or “% transmission” refers to the ratio of transmitted light to incident light, and may be measured according to ASTM D 1003-07.

“Polycarbonate” as used herein refers to an oligomer or a polymer comprising residues of one or more monomers, joined by carbonate linkages.

“Thermal stability” as used herein refers to resistance of a polymer to molecular weight degradation under thermal conditions. Thus, a polymer with poor thermal stability may show significant molecular weight degradation under thermal conditions, such as during extrusion, molding, thermoforming, hot-pressing, and like conditions. Molecular weight degradation may also be manifest through color formation and/or in the degradation of other properties such as weatherability, gloss, mechanical properties, and/or thermal properties. Molecular weight degradation can also cause significant variation in processing conditions such as melt viscosity changes.

The term “crosslink” and its variants refer to the formation of a stable covalent bond between two polymers/oligomers. This term is intended to encompass the formation of covalent bonds that result in network formation, or the formation of covalent bonds that result in chain extension. The term “cross-linkable” refers to the ability of a polymer/oligomer to form such stable covalent bonds.

The present disclosure refers to “polymers,” “oligomers”, and “compounds”. A polymer is a large molecule composed of multiple repeating units chained together, the repeating units being derived from a monomer. One characteristic of a polymer is that different molecules of a polymer will have different lengths, and a polymer is described as having a molecular weight that is based on the average value of the chains (e.g. weight average or number average molecular weight). The art also distinguishes between an “oligomer” and a “polymer”, with an oligomer having only a few repeating units, while a polymer has many repeating units. For purposes of this disclosure, the term “oligomer” refers to such molecules having a weight average molecular weight of less than 15,000, and the term “polymer” refers to molecules having a weight average molecular weight of 15,000 of more, as measured by GPC using polycarbonate molecular weight standards. In contrast, for a compound, all molecules will have the same molecular weight. Compared to a polymer, a compound is a small molecule. These molecular weights are measured prior to any UV exposure.

Additives

The present disclosure relates to photoactive additives (PAA), and to compositions containing such additives. When the photoactive additive is added to one or more base resins and is then exposed to the appropriate wavelength of light, the resulting composition will have improved anti-drip and flame retardant properties compared to the base resins alone or to the composition prior to the light exposure. For example, the chemical resistance, propensity to drip during burning, or the propensity to form a hole when exposed to a flame can be improved. Improved flame resistance performance characteristics may include flame out time (FOT) and time to drip (TTD). The compositions, blended or neat, can be used to provide thin-walled materials that are UL94 5VA compliant. The compositions can be used to provide thin-walled materials that are 5VA compliant and highly transparent. The compositions may also exhibit good chemical resistance, tear resistance, impact strength, ductility, hydrolytic stability, and/or weatherability.

Generally, the photoactive additives (PAA) of the present disclosure include photoactive moieties that are covalently linked together through a first linker moiety and possibly a secondary linker moiety. The photoactive moieties contain a ketone group that, when exposed to the appropriate wavelength(s) of ultraviolet light, will form a stable covalent bond between the PAA and the polymeric resin. The PAA also contains polysiloxane blocks to promote migration, as explained further herein. The PAA should be stable at conventional blending, forming, and processing temperatures (i.e. stable at 350° C. or above). The PAA also should not induce the degradation of the polymeric resin with which it is blended.

The term “photoactive moiety” refers to a moiety that, when exposed to ultraviolet light of the appropriate wavelength, crosslinks with another molecule. Thus, for example, the bisphenol-A monomer in a bisphenol-A homopolymer would not be considered a photoactive moiety, even though photo-Fries rearrangement can occur upon exposure to light, because the atoms do not participate in crosslinking but merely in rearrangement of the polymer backbone.

The photoactive additive is formed from a reaction mixture containing at least a first photoactive moiety, a first linker moiety, and a polysiloxane monomer. The photoactive moiety comprises (i) a ketone group and (ii) two hydroxyl groups. The first linker moiety comprises a plurality of functional groups that can react with the hydroxyl group(s) of the photoactive moiety and the polysiloxane monomer. The reaction product is the photoactive additive (PAA). The molar ratio of the photoactive moiety to the first linker moiety can be from 1:2 to 1:200. The molar ratio of the photoactive moiety to the polysiloxane monomer can be from 1:20 to 20:1. An end-capping agent may also be included. A diol chain extender is usually also included. The end-capping agent and the diol chain extender do not have photoactive properties.

The term “ketone group” refers to a carbonyl group (—CO—) that is bonded to two other carbon atoms (i.e. —R—CO—R′—). The two other carbon atoms can be in an aliphatic group or in an aromatic group. An ester group and a carboxylic acid group are not considered to be a ketone group because the carbonyl group is bonded to one carbon atom and an oxygen atom.

In many embodiments, the hydroxyl group(s) of the photoactive moiety are phenolic groups. The term “phenolic group” refers to a phenyl group (—C₆H₄—) with a hydroxyl group (—OH) covalently bonded to a carbon atom in the phenyl group. In other embodiments, the hydroxyl group(s) of the photoactive moiety are carboxyl groups.

The photoactive moiety can be a hydroxyphenone, wherein the phenolic group is directly bonded to the ketone group. In particular embodiments, the photoactive moiety contains only two phenolic groups. Examples of such photoactive moieties include those having the structure of one of Formulas (16)-(21):

wherein R is H, alkyl, or aryl.

The compound of Formula (16) is a dihydroxyphenyl-phenylmethanone. The compound of Formula (17) is a bis(hydroxyphenyl)methanone. The compounds of Formulas (16) or (17) could also be referred to as dihydroxybenzophenones. The compound of Formula (18) is a 1-dihydroxyphenyl-2-phenylethane-1,2-dione. The compound of Formula (19) is a 1,2-bis(hydroxyphenyl)ethane-1,2-dione. The compounds of Formulas (18) or (19) could also be referred to as dihydroxybenzils. The compound of Formula (20) is a 1-(dihydroxyphenyl)-2-hydrocarboxy-2-phenylethanone. The compound of Formula (21) is a 1,2-bis(hydroxyphenyl)-2-hydrocarboxy-ethanone.

Again, in some other embodiments, the R and R′ groups attached to the ketone group form a ring structure. In such embodiments, the aromatic rings can include both aryl rings or heteroaryl rings. Examples of such photoactive moieties include those having the structure of one of Formulas (22)-(29):

The compounds of Formula (22) and (23) are a dihydroxy-9,10-anthraquinone. The compounds of Formula (24) and (23) are a dihydroxy-9-fluorenone. The compounds of Formula (26) and (23) are a dihydroxydibenzo[1,3-e:1′,2′-f][7]annulen-11-one. The compounds of Formula (28) and (23) are a dihydroxythioxanthen-9-one. The different formulas reflect the location of the two hydroxyl groups (either on the same ring, or on a different ring). In particular embodiments, the photoactive moiety is 4,4′-dihydroxybenzophenone

The photoactive moiety is reacted with one or more first linker moieties, and with a polysiloxane monomer. At least one of the first linker moieties comprises a plurality of functional groups that can react with the phenolic group(s) of the photoactive moiety and the polysiloxane monomer. Examples of such functional groups include a carboxylic acid (and anhydrides thereof), an acyl halide, an alkyl ester, and an aryl ester. These functional groups are illustrated below in general formula (A):

where Y is hydroxyl, halogen, alkoxy, or aryloxy. The functional groups can be joined to an aliphatic group or an aromatic group which serves as a “backbone” for the linker moiety. In particular embodiments, the linker moiety can have two, three, four, or even more functional groups.

Some examples of first linker moieties which have two functional groups and can react with the photoactive moieties include those having the structure of one of Formulas (30, (32), or (33):

where Y is hydroxyl, halogen, alkoxy, or aryloxy; and where n is 1 to 20. It should be noted that Formula (33) encompasses isophthalic acid and terephthalic acid.

Some examples of first linker moieties which have three functional groups and can react with the photoactive moieties include those having the structure of one of Formulas (36)-(38):

where Y is hydroxyl, halogen, alkoxy, or aryloxy.

Some examples of first linker moieties which have four functional groups and can react with the photoactive moieties include those having the structure of one of Formulas (39)-(41):

where Y is hydroxyl, halogen, alkoxy, or aryloxy.

In some embodiments, functional groups can be provided by short oligomers, including oligomers containing glycidyl methacrylate monomers with styrene or methacrylate monomers, or epoxidized novolac resins. These oligomers can permit the desired the number of functional groups to be provided. Such oligomers are generalized by the structure of Formula (42):

where E is hydrogen or an endcapping agent, p is the number of methacrylate monomers, q is the number of methacrylate monomers, r is the number of styrene monomers, and t is the number of epoxidized novolac (phenol-formaldehyde)monomers. Generally, p+q+r+t 20. When the oligomer contains glycidyl methacrylate monomers with styrene or methacrylate monomers, generally t=0 and q≧1. Similarly, for novolac resins, p=q=r=0. The epoxy groups can be reacted with the phenolic group of the photoactive moiety.

A polysiloxane monomer is also reacted with the photoactive moiety and the first linker moiety. This results in an oligomer/polymer containing polycarbonate blocks and polysiloxane blocks. One exemplary polysiloxane monomer has the structure of Formula (I):

wherein each Ar is independently aryl; each R is independently alkyl, alkoxy, alkenyl, alkenyloxy, aryl, aryloxy, arylalkyl, or alkylaryl; and D is an average value of 2 to about 1000, specifically about 2 to about 500, more specifically about 10 to about 75. Compounds of this formula may be obtained by the reaction of a dihydroxyarylene compound with, for example, an alpha,omega-bisacetoxypolydiorangonosiloxane under phase transfer conditions.

Another exemplary polysiloxane monomer has the structure of Formula (II):

wherein each R is independently alkyl, alkoxy, alkenyl, alkenyloxy, aryl, aryloxy, arylalkyl, or alkylaryl; and D is an average value of 2 to about 1000, specifically about 2 to about 500, more specifically about 10 to about 75; each M is independently cyano, nitro, alkyl, alkoxy, alkenyl, alkenyloxy, aryl, aryloxy, arylalkyl, or alkylaryl; each n is independently an integer from 0 to 4; and each R₂ is independently an aliphatic group. Compounds of this formula may be obtained by the reaction of a siloxane hydride with an aliphatically unsaturated monohydric phenol. Suitable aliphatically unsaturated monohydric phenols include, for example, eugenol, 2-alkylphenol, 4-allyl-2-methylphenol, 4-allyl-2-phenylphenol, 4-allyl-2-t-butoxyphenol, 4-phenyl-2-phenylphenol, 2-methyl-4-propylphenol, 2-allyl-4,6-dimethylphenol, 2-allyl-6-methoxy-4-methylphenol and 2-allyl-4,6-dimethylphenol. Mixtures comprising at least one of the foregoing may also be used.

A third exemplary polysiloxane monomer has the structure of Formula (III):

wherein each R is independently alkyl, alkoxy, alkenyl, alkenyloxy, aryl, aryloxy, arylalkyl, or alkylaryl; each R₆ is independently a divalent C₁-C₃₀ organic group such as a C₁-C₃₀ alkyl, C₁-C₃₀ aryl, or C₁-C₃₀ alkylaryl; and E is an average value of 2 to about 1000, specifically about 2 to about 500, or about 10 to about 200, or more specifically about 10 to about 75. It is noted that D and E have identical values in Formulas (I)-(III).

Specific examples of polysiloxane monomers that can be used herein Formulas (a) through (d):

where E is an average value from 10 to 200.

If desired, the photoactive additive can be formed from a reaction mixture containing the photoactive moiety, the first linker moiety, the polysiloxane monomer, and one or more diol chain extenders. The diol chain extender is a molecule that contains only two hydroxyl groups and is not photoactive when exposed to light. The chain extender can be used to provide a desired level of miscibility when the additive is mixed with other polymeric resins.

A first exemplary chain extender is a bisphenol of Formula (A):

wherein R^(a) and R^(b) each represent a halogen atom or a monovalent hydrocarbon group and may be the same or different; p and q are each independently integers of 0 to 4; and A represents one of the groups of formula (A-1):

wherein R^(c) and R^(d) each independently represent a hydrogen atom or a monovalent linear or cyclic hydrocarbon group and R^(e) is a divalent hydrocarbon group.

Specific examples of the types of bisphenol compounds that may be represented by Formula (A) include 1,1-bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (hereinafter “bisphenol-A” or “BPA”), 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, 1,1-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)n-butane, 2,2-bis(4-hydroxy-1-methylphenyl)propane, and 1,1-bis(4-hydroxy-t-butylphenyl)propane; 4,4′-(1-phenylethane-1,1-diyl)diphenol or 1,1-bis(4-hydroxyphenyl)-1-phenyl-ethane (bisphenol-AP); and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane) (bisphenol TMC).

A second exemplary chain extender is a bisphenol of Formula (B):

wherein each R^(k) is independently a C₁₋₁₀ hydrocarbon group, and n is 0 to 4. The halogen is usually bromine. Examples of compounds that may be represented by Formula (B) include resorcinol, substituted resorcinol compounds such as 5-methyl resorcinol, 5-phenyl resorcinol, or 5-cumyl resorcinol; catechol; hydroquinone; and substituted hydroquinones such as 2-methyl hydroquinone, 2-t-butyl hydroquinone, 2-phenyl hydroquinone, 2-cumyl hydroquinone, or 2,3,5,6-tetramethyl hydroquinone.

A third exemplary chain extender is an aliphatic diol of Formula (C):

wherein each X is independently hydrogen, halogen, or alkyl; and j is an integer from 1 to 20. Examples of an aliphatic diol include ethylene glycol, propanediol, 2,2-dimethyl-propanediol, 1,6-hexanediol, and 1,12-dodecanediol.

A fifth exemplary diol chain extender is a dihydroxy compound of Formula (D), which may be useful for high heat applications:

wherein R¹³ and R¹⁵ are each independently a halogen or a C₁-C₆ alkyl group, R¹⁴ is a C₁-C₆ alkyl, phenyl, or phenyl substituted with up to five halogens or C₁-C₆ alkyl groups, and c is 0 to 4. In a specific embodiment, R¹⁴ is a C₁-C₆ alkyl or phenyl group. In still another embodiment, R¹⁴ is a methyl or phenyl group. In another specific embodiment, each c is 0. Compounds of Formula (D) include 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP).

Other dihydroxy compounds (i.e. diol chain extenders) that might impart high Tgs to the polycarbonate as a copolycarbonate are dihydroxy compounds having adamantane units, as described in U.S. Pat. Nos. 7,112,644 and 3,516,968, which are fully incorporated herein by reference. A compound having adamantane units may have repetitive units of the following formula (E) for high heat applications:

wherein R₁ represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aryl-substituted alkenyl group having 7 to 13 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; R₂ represents a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aryl-substituted alkenyl group having 7 to 13 carbon atoms, or a fluoroalkyl group having 1 to 12 carbon atoms; m represents an integer of 0 to 4; and n represents an integer of 0 to 14.

Other dihydroxy compounds that might impart high Tgs to the polycarbonate as a copolycarbonate are dihydroxy compounds having fluorene-units, as described in U.S. Pat. No. 7,244,804. One such fluorene-unit containing dihydroxy compound is represented by the following formula (F) for high heat applications:

wherein R₁ to R₄ are each independently a hydrogen atom, a hydrocarbon group with 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom.

Another diol chain extender that could be used is an isosorbide. A monomer unit derived from isosorbide may be an isorbide-bisphenol unit of Formula (G):

wherein R₁ is an isosorbide unit and R₂-R₉ are each independently a hydrogen, a halogen, a C₁-C₆ alkyl, a methoxy, an ethoxy, or an alkyl ester.

The R₁ isosorbide unit may be represented by Formula (G-a):

The isosorbide unit may be derived from an isosorbide, a mixture of isosorbide, a mixture of isomers of isosorbide, and/or from individual isomers of isosorbide. The stereochemistry for the isosorbide-based carbonate units of Formula (I) is not particularly limited. These diols may be prepared by the dehydration of the corresponding hexitols. Hexitols are produced commercially from the corresponding sugars (aldohexose). Aliphatic diols include 1,4:3,6-dianhydro-D glucitol; 1,4:3,6-dianhydro-D mannitol; and 1,4:3,6-dianhydro-L iditol; and any combination thereof. Isosorbides are available commercially from various chemical suppliers including Cargill, Roquette, and Shanxi. The isosorbide-bisphenol may have a pKa of between 8 and 11.

As previously explained, a first photoactive moiety is reacted with a first linker moiety, a polysiloxane monomer, and a diol chain extender to obtain the photoactive additive. In some embodiments, a secondary linker moiety is included in the reaction mixture. The secondary linker moiety has at least three functional groups, each of which can react with the functional groups of the first linker moiety. Generally, the functional groups of the secondary linker moiety are hydroxyl groups.

Some examples of secondary linker moieties which have three functional groups and can react with the first linker moiety include those having the structure of one of Formulas (43)-(46):

Some examples of secondary linker moieties which have four functional groups and can react with the first linker moiety include those having the structure of one of Formulas (47)-(48):

In some embodiments, the secondary linker moiety can be an oligomer, made from an epoxidized novolac monomer. These oligomers can permit the desired number of functional groups to be provided. Such oligomers are generalized by the structure of Formula (49):

wherein E is hydrogen or an endcapping agent; and t is an integer from 1 to 20.

An end-capping agent is generally used to terminate any polymer chains of the photoactive additive. The end-capping agent (i.e. chain stopper) is a monohydroxy compound, a mono-acid compound, or a mono-ester compound. Exemplary endcapping agents include phenol, p-cumylphenol (PCP), resorcinol monobenzoate, p-tert-butylphenol, octylphenol, p-cyanophenol, and p-methoxyphenol. If not modified with other adjectives, the term “end-capping agent” is used herein to denote a compound that is not photoactive when exposed to light. For example, the end-capping agent does not contain a ketone group. The photoactive additive may comprise about 0.5 mole % to about 5.0 mole % endcap groups derived from the end-capping agent.

However, in some embodiments, the end-capping agent can be a photoactive end-capping agent, such as a monohydroxybenzophenone. Suitable monohydroxybenzophenone end-capping agents include, but are not limited to, 2-hydroxybenzophenone, 3-hydroxybenzophenone, 4-hydroxybenzophenone, 4-hydroxybenzoylbenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-stearoxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, and 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid. In one preferred embodiment, the monohydroxybenzophenone chain stopper is a 2-hydroxybenzophenone, 3-hydroxybenzophenone, or 4-hydroxybenzophenone, each of which may be further substituted with one or more additional substituents, provided the monohydroxybenzophenone still functions as a chain-stopper. In another preferred embodiment, the monohydroxybenzophenone is 4-hydroxybenzophenone.

The cross-linkable polycarbonates (also referred to as “non-cross-linked polycarbonates”) may comprise about 0.5 mole % to about 5 mole % endcap groups derived from a monohydroxybenzophenone, about 1 mole % to about 3 mole % endcap groups derived from a monohydroxybenzophenone, about 1.7 mole % to about 2.5 mole % endcap groups derived from a monohydroxybenzophenone, about 2 mole % to about 2.5 mole % endcap groups derived from a monohydroxybenzophenone, or about 2.5 mole % to about 3.0 mole % endcap groups derived from a monohydroxybenzophenone.

Depending on the selection of the first linker moiety, the photoactive additive of the present disclosure may be a polyester-polycarbonate copolymer. The molar ratio of ester units to carbonate units in the polyester-polycarbonate may vary broadly, for example 1:99 to 99:1, specifically 10:90 to 90:10, more specifically 25:75 to 75:25, optionally expanded depending on the desired properties of the final composition. The polyester units may be derived from an aliphatic or aromatic dicarboxylic acid. Aliphatic dicarboxylic acids may have from 6 to about 36 carbon atoms, optionally from 6 to 20 carbon atoms. Exemplary aliphatic dicarboxylic acids include adipic acid, sebacic acid, 3,3-dimethyl adipic acid, 3,3,6-trimethyl sebacic acid, 3,3,5,5-tetramethyl sebacic acid, azelaic acid, dodecanedioic acid, dimer acids, cyclohexane dicarboxylic acids, dimethyl cyclohexane dicarboxylic acid, norbornane dicarboxylic acids, adamantane dicarboxylic acids, cyclohexene dicarboxylic acids, or C₁₄, C₁₈ and C₂₀ diacids. Exemplary aromatic dicarboxylic acids include isophthalic or terephthalic acid, 1,2-di(p-carboxyphenyl)ethane, 4,4′-dicarboxydiphenyl ether, 4,4′-bisbenzoic acid; 1,4-, 1,5-, or 2,6-naphthalenedicarboxylic acids; and combinations comprising at least one of the foregoing acids. A specific dicarboxylic acid mixture comprises a combination of isophthalic acid and terephthalic acid wherein the weight ratio of isophthalic acid to terephthalic acid is about 91:9 to about 2:98.

The polyester unit of a polyester-polycarbonate may be derived from the reaction of a combination of isophthalic and terephthalic diacids (or derivatives thereof) with resorcinol. In another embodiment, the polyester unit of a polyester-polycarbonate may be derived from the reaction of a combination of isophthalic acid and terephthalic acid with bisphenol-A. In an embodiment, the polycarbonate units may be derived from bisphenol-A. In another specific embodiment, the polycarbonate units may be derived from resorcinol and bisphenol-A in a molar ratio of resorcinol carbonate units to bisphenol-A carbonate units of 1:99 to 99:1.

The photoactive additives of the present disclosure can be a compound, an oligomer, or a polymer. The oligomer has a weight average molecular weight (Mw) of less than 15,000, including 10,000 or less. The polymeric photoactive additives of the present disclosure have a Mw of 15,000 or higher. In particular embodiments, the Mw is between 17,000 and 80,000 Daltons, or between 17,000 and 35,000 Daltons. These molecular weights are measured prior to any UV exposure. The Mw may be varied as desired. Polymers/oligomers with relatively higher Mw's generally retain their mechanical properties better, while polymers/oligomers with relatively lower Mw's generally have better flow properties. In some particular embodiments, the Mw of the photoactive additives is about 5,000 or less.

In this regard, when the photoactive additives (PAA) are blended with a polymeric base resin and molded, it is desired to promote the migration of the PAA to the air-polymer interface, i.e. the surface of the article. Upon exposure to the appropriate wavelength, crosslinking will occur and result in a molded article having improved flame retardant properties and chemical resistance.

Due to its very low surface energies (20-22 mN/m) and low solubility parameters, the polysiloxane blocks in the PAA provided by the polysiloxane monomer tends to phase separate in bulk and also migrate to the air-polymer interface. The surface compositions and properties of the final molded article will depend on the amount and the block length of silicone in the polysiloxane monomer, the type and nature of the base resin (e.g. amorphous or crystalline morphology), method of preparation, and annealing conditions.

FIG. 1 and FIG. 2 illustrate two photoactive additives of the present disclosure. These are exemplary, and are not intended to be limiting. These two figures all use a eugenol-endcapped polysiloxane monomer of Formula (II). The full formula of that monomer is identified as Formula (II-a) below:

However, to reduce the space needed for the figures, this polysiloxane monomer is abbreviated as:

In FIG. 1, the photoactive additive is a terpolymer formed from the reaction of p-cumylphenol (endcap), 4,4′-dihydroxybenzophenone (photoactive), bisphenol-A (chain extender), polysiloxane monomer, and phosgene (linker). The resulting additive contains carbonate linkages, and is an oligomer or polymer. It should be noted that this figure only shows the repeating units in their relative molar amounts (p, q, r), and should not be construed as disclosing a specific block arrangement of the monomers.

In FIG. 2, the photoactive additive is a dipolymer formed from the reaction of 4-hydroxybenzophenone (photoactive endcap), polysiloxane, bisphenol-A (chain extender), and phosgene (linker). The resulting additive contains carbonate linkages, and is an oligomer or polymer. It should be noted that this figure only shows the repeating units in their relative molar amounts (p, q), and should not be construed as disclosing a specific block arrangement of the monomers.

One crosslinking mechanism of the additives is believed to be due to hydrogen abstraction by the ketone group from an alkyl group that acts as a hydrogen donor and subsequent coupling of the resulting radicals. This mechanism is illustrated in FIG. 3 with reference to a benzophenone (the photoactive moiety) and a bisphenol-A (BPA) monomer. Upon exposure to UV, the oxygen atom of the benzophenone abstracts a hydrogen atom from a methyl group on the BPA monomer and becomes a hydroxyl group. The methylene group then forms a covalent bond with the carbon of the ketone group. Put another way, the ketone group of the benzophenone could be considered to be a photoactive group. It should be noted that the presence of an abstractable hydrogen is critical for this reaction to occur. Other mechanisms may occur after the initial abstraction event with base resins containing unsaturated bonds or reactive side groups.

In particular embodiments, the photoactive additives (PAAs) disclosed herein are cross-linkable polycarbonate-polysiloxane copolymers comprising repeating units derived from a dihydroxybenzophenone monomer (i.e. of Formula (17)). These polycarbonates, prior to cross-linking, can be provided as thermally stable high melt-flow polymers, and can thus be used to fabricate a variety of thin-walled products (e.g., 3 mm or less). These products may subsequently be treated (e.g., with UV-radiation) to affect cross-linking, thereby providing thin-walled materials that meet desired performance requirements (e.g., 5VA performance, chemical resistance, transparency). The cross-linked materials, in addition to flame resistance and chemical resistance, may retain or exhibit superior mechanical properties (e.g., impact resistance, ductility) as compared to the composition prior to cross-linking.

The dihydroxybenzophenone monomers of the cross-linkable polycarbonates provide a photoactive ketone group for cross-linking the polycarbonates. Treatment of a cross-linkable polycarbonate of the present disclosure with a suitable dose of UV radiation initiates a cross-linking reaction between the dihydroxybenzophenone carbonyl carbon and the carbon atom of another functional group (e.g., a methylene carbon atom, such as in bisphenol-A) in the same polymer or another polymer in the composition.

The cross-linkable polycarbonates of the present disclosure include homopolycarbonates, copolymers comprising different moieties in the carbonate (referred as “copolycarbonates”), copolymers comprising carbonate units and other types of polymer units such as polyester units, polysiloxane units, and combinations comprising at least one homopolycarbonate and copolycarbonate. For reference, the term “dipolymer” refers to copolymers derived specifically from two different monomers, and the term “terpolymer” refers to copolymers derived specifically from three different monomers

Because the cross-linkable polycarbonate is a copolymer, the monomers may be randomly incorporated into the polycarbonate. A random copolymer may have several block sequences and alternate sequences that follow a statistical distribution. In a random x:(1-x) copolymer, wherein x is the mole percent of a first monomer and 1-x is the mole percent of the other monomers, one can calculate the distribution of each monomer using peak area values determined by ¹³C NMR, for example. The copolymer can be an alternating copolymer with alternating I and O units (—I—O—I—O—I—O—I—O—), or I and O units arranged in a repeating sequence (e.g. a periodic copolymer having the formula: (I—O—I—O—O—I—I—I—O—O—O)n). The cross-linkable polycarbonate copolymer may be a statistical copolymer in which the sequence of monomer residues follows a statistical rule. The copolymer may also be a block copolymer that comprises two or more homopolymer subunits linked by covalent bonds (—I—I—I—I—I—O—O—O—O—O—). The union of the homopolymer subunits may require an intermediate non-repeating subunit, known as a junction block. Block copolymers with two or three distinct blocks are called diblock copolymers and triblock copolymers, respectively.

In embodiments, the cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure contain from about 0.5 mole % to about 50 mole % of the dihydroxybenzophenone monomer (i.e. repeating units derived from the dihydroxybenzophenone monomer). In more specific embodiments, the copolymers contain from about 1 mole % to about 3 mole %, or from about 1 mole % to about 6 mole %, from about 10 mole % to about 25 mole %%, or from about 0.5 mole % to about 25 mole % of the dihydroxybenzophenone monomer. The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure contain the polysiloxane monomer in an amount such that the copolymer contains from about 1 wt % to about 25 wt % of siloxane units, or from about 1 wt % to about 10 wt % of siloxane units. The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure also contain from about 50 mole % to about 95.5 mole % of the diol chain extender. In this regard, the polycarbonate-polysiloxane copolymers are usually terpolymers.

The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure may have a polydispersity index (PDI) of about 2.0 to about 5.0, about 2.0 to about 3.0, or about 2.0 to about 2.5. The PDI is measured prior to any UV exposure.

It is noted that the molecular weight (both weight-average and number-average) of the photoactive additive/cross-linkable polycarbonate-polysiloxane copolymer can be measured using two different kinds of detectors. More specifically, the molecular weight can be measured using an ultraviolet (UV) detector or using a refractive index (RI) detector, using GPC and calibrated to polycarbonate standards for both detectors.

The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure may have a melt flow rate (often abbreviated MFR), which measures the rate of extrusion of a composition through an orifice at a prescribed temperature and load. In certain embodiments, the polycarbonates may have an MFR of 6 to 15 grams/10 min, 6 to 8 grams/10 min, 6 to 12 grams/10 min, 2 to 30 grams/10 min, 5 to 30 grams/10 min, 2 to 100 grams/10 min, 8 to 12 grams/10 min, 8 to 10 grams/10 min, 20 to 30 grams/10 min, 45 to 55 grams/10 min, or 75 to 100 grams/10 min, using the ASTM D1238 method, 1.2 kg load, 300° C. temperature, 360 second dwell.

The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure may have a biocontent of 2 wt % to 90 wt %; 5 wt % to 25 wt %; 10 wt % to 30 wt %; 15 wt % to 35 wt %; 20 wt % to 40 wt %; 25 wt % to 45 wt %; 30 wt % to 50 wt %; 35 wt % to 55 wt %; 40 wt % to 60 wt %; 45 wt % to 65 wt %; 55 wt % to 70% wt %; 60 wt % to 75 wt %; 50 wt % to 80 wt %; or 50 wt % to 90 wt %. The biocontent may be measured according to ASTM D6866.

The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure may have a modulus of elasticity of greater than or equal to 2200 megapascals (MPa), greater than or equal to 2310 MPa, greater than or equal to 2320 MPa, greater than or equal to 2330 MPa, greater than or equal to 2340 MPa, greater than or equal to 2350 MPa, greater than or equal to 2360 MPa, greater than or equal to 2370 MPa, greater than or equal to 2380 MPa, greater than or equal to 2390 MPa, greater than or equal to 2400 MPa, greater than or equal to 2420 MPa, greater than or equal to 2440 MPa, greater than or equal to 2460 MPa, greater than or equal to 2480 MPa, greater than or equal to 2500 MPa, or greater than or equal to 2520 MPa as measured by ASTM D 790 at 1.3 mm/min, 50 mm span.

In embodiments, the cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure may have a flexural modulus of 2,200 to 2,500, preferably 2,250 to 2,450, more preferably 2,300 to 2,400 MPa. In other embodiments, the cross-linkable polycarbonates of the present disclosure may have a flexural modulus of 2,300 to 2,600, preferably 2,400 to 2,600, more preferably 2,450 to 2,550 MPa. The flexural modulus is also measured by ASTM D790.

The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure may have a tensile strength at break of greater than or equal to 60 megapascals (MPa), greater than or equal to 61 MPa, greater than or equal to 62 MPa, greater than or equal to 63 MPa, greater than or equal to 64 MPa, greater than or equal to 65 MPa, greater than or equal to 66 MPa, greater than or equal to 67 MPa, greater than or equal to 68 MPa, greater than or equal to 69 MPa, greater than or equal to 70 MPa, greater than or equal to 71 MPa, greater than or equal to 72 MPa, greater than or equal to 73 MPa, greater than or equal to 74 MPa, greater than or equal to 75 MPa as measured by ASTM D 638 Type I at 50 mm/min.

The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure may possess a ductility of greater than or equal to 60%, greater than or equal to 65%, greater than or equal to 70%, greater than or equal to 75%, greater than or equal to 80%, greater than or equal to 85%, greater than or equal to 90%, greater than or equal to 95%, or 100% in a notched izod test at −20° C., −15° C., −10° C., 0° C., 5° C., 10° C., 15° C., 20° C., 23° C., 25° C., 30° C., or 35° C. at a thickness of 3.2 mm according to ASTM D 256-10.

The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure may have a notched Izod impact strength (NII) of greater than or equal to 500 J/m, greater than or equal to 550 J/m, greater than or equal to 600 J/m, greater than or equal to 650 J/m, greater than or equal to 700 J/m, greater than or equal to 750 J/m, greater than or equal to 800 J/m, greater than or equal to 850 J/m, greater than or equal to 900 J/m, greater than or equal to 950 J/m, or greater than or equal to 1000 J/m, measured at 23° C. according to ASTM D 256.

The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure may have a heat distortion temperature of greater than or equal to 110° C., 111° C., 112° C., 113° C., 114° C., 115° C., 116° C., 117° C., 118° C., 119° C., 120° C., 121° C., 122° C., 123° C., 124° C., 125° C., 126° C., 127° C., 128° C., 129° C., 130° C., 131° C., 132° C., 133° C., 134° C., 135° C., 136° C., 137° C., 138° C., 139° C., 140° C., 141° C., 142° C., 143° C., 144° C., 145° C., 146° C., 147° C., 148° C., 149° C., 150° C., 151° C., 152° C., 153° C., 154° C., 155° C., 156° C., 157° C., 158° C., 159° C., 160, 161° C., 162° C., 163° C., 164° C., 165° C., 166° C., 167° C., 168° C., 169° C., or 170° C., as measured according to ASTM D 648 at 1.82 MPa, with 3.2 mm thick unannealed mm bar.

The cross-linkable polycarbonate-polysiloxane copolymers of the present disclosure may have a percent haze value of less than or equal to 10.0%, less than or equal to 8.0%, less than or equal to 6.0%, less than or equal to 5.0%, less than or equal to 4.0%, less than or equal to 3.0%, less than or equal to 2.0%, less than or equal to 1.5%, less than or equal to 1.0%, or less than or equal to 0.5% as measured at a certain thickness according to ASTM D 1003-07. The polycarbonate haze may be measured at a 2.0, 2.2, 2.4, 2.54, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, or a 4.0 millimeter thickness. The polycarbonate may be measured at a 0.125 inch thickness.

The polycarbonate-polysiloxane copolymers may have a light transmittance greater than or equal to 50%, greater than or equal to 60%, greater than or equal to 65%, greater than or equal to 70%, greater than or equal to 75%, greater than or equal to 80%, greater than or equal to 85%, greater than or equal to 90%, greater than or equal to 95%, greater than or equal to 96%, greater than or equal to 97%, greater than or equal to 98%, greater than or equal to 99%, greater than or equal to 99.1%, greater than or equal to 99.2%, greater than or equal to 99.3%, greater than or equal to 99.4%, greater than or equal to 99.5%, greater than or equal to 99.6%, greater than or equal to 99.7%, greater than or equal to 99.8%, or greater than or equal to 99.9%, as measured at certain thicknesses according to ASTM D 1003-07. The polycarbonate transparency may be measured at a 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, or a 4.0 millimeter thickness.

In particular embodiments, the photoactive cross-linkable polycarbonate-polysiloxane copolymer is formed from a dihydroxybenzophenone, a polysiloxane monomer, a diol chain extender, phosgene, and one or more end-capping agents. Most desirably, the dihydroxybenzophenone is 4,4′-dihydroxybenzophenone. In preferred embodiments, the diol chain extender is bisphenol-A, and the end-capping agent is p-cumylphenol. The resulting photoactive additive (i.e. cross-linkable polycarbonate-polysiloxane copolymer) can comprise from about 0.5 mole % to 50 mole % of the dihydroxybenzophenone; from about 50 mole % to about 95.5 mole % of the diol chain extender; and an amount of the polysiloxane monomer sufficient to provide 1 wt % to 25 wt % of siloxane to the additive.

Processes

An interfacial polycondensation polymerization process for bisphenol-A (BPA) based polycarbonates can be used to prepare the photoactive additives (PAAs) of the present disclosure. Although the reaction conditions for interfacial polymerization can vary, an exemplary process generally involves dissolving or dispersing one or more dihydric phenol reactants (e.g. the dihydroxybenzophenone, polysiloxane monomer, bisphenol-A) in water, adding the resulting mixture to a water-immiscible solvent medium, and contacting the reactants with a carbonate precursor (e.g. phosgene) in the presence of a catalyst (e.g. triethylamine, TEA).

Four different processes are disclosed herein for producing some embodiments of the photoactive additive which contain carbonate linkages. Each process includes the following ingredients: a dihydroxybenzophenone, a diol chain extender, an end-capping agent, a carbonate precursor, a base, a tertiary amine catalyst, water, and a water-immiscible organic solvent, and optionally a branching agent. The dihydroxybenzophenone is the photoactive moiety. It should be noted that more than one of each ingredient can be used to produce the photoactive additive. Many of these ingredients have been previously described.

The carbonate precursor may be, for example, a carbonyl halide such as carbonyl dibromide or carbonyl dichloride (also known as phosgene), or a haloformate such as a bishaloformate of a dihydric phenol (e.g., the bischloroformate of bisphenol-A, hydroquinone, or the like) or a glycol (e.g., the bishaloformate of ethylene glycol, neopentyl glycol, polyethylene glycol, or the like). Combinations comprising at least one of the foregoing types of carbonate precursors can also be used. In certain embodiments, the carbonate precursor is phosgene, a triphosgene, diacyl halide, dihaloformate, dicyanate, diester, diepoxy, diarylcarbonate, dianhydride, diacid chloride, or any combination thereof. An interfacial polymerization reaction to form carbonate linkages may use phosgene as a carbonate precursor, and is referred to as a phosgenation reaction. Many such carbonate precursors correspond to a structure of Formulas (30), (32), or (33).

The base is used for the regulation of the pH of the reaction mixture. In particular embodiments, the base is an alkali metal hydroxide, such as sodium hydroxide (NaOH) or potassium hydroxide (KOH).

A tertiary amine catalyst is used for polymerization. Exemplary tertiary amine catalysts that can be used are aliphatic tertiary amines such as triethylamine (TEA), N-ethylpiperidine, 1,4-diazabicyclo[2.2.2]octane (DABCO), tributylamine, cycloaliphatic amines such as N,N-diethyl-cyclohexylamine and aromatic tertiary amines such as N,N-dim ethyl aniline.

Sometimes, a phase transfer catalyst is also used. Among the phase transfer catalysts that can be used are catalysts of the formula (R³⁰)₄Q⁺X, wherein each R³⁰ is the same or different, and is a C₁-C₁₀ alkyl group; Q is a nitrogen or phosphorus atom; and X is a halogen atom, C₁-C₈ alkoxy group, or C₆-C₁₈ aryloxy group. Exemplary phase transfer catalysts include, for example, [CH₃(CH₂)₃]₄NX, [CH₃(CH₂)₃]₄PX, [CH₃(CH₂)₅]₄NX, [CH₃(CH₂)₆]₄NX, [CH₃(CH₂)₄]₄NX, CH₃[CH₃(CH₂)₃]₃NX, and CH₃[CH₃(CH₂)₂]₃NX, wherein X is Cl⁻, Br⁻, a C₁-C₈ alkoxy group or a C₆-C₁₈ aryloxy group, such as methyltributylammonium chloride.

The most commonly used water-immiscible solvents include methylene chloride, 1,2-dichloroethane, chlorobenzene, toluene, and the like.

In the first process, sometimes referred to as the “upfront” process, the dihydroxybenzophenone, diol chain extender, end-capping agent, catalyst, water, and water-immiscible solvent are combined upfront in a vessel to form a reaction mixture. The reaction mixture is then exposed to the carbonate precursor, for example by phosgenation, while the base is co-added to regulate the reaction pH, to obtain the photoactive additive.

In the second process, also known as the “solution addition” process, the dihydroxybenzophenone, diol chain extender, tertiary amine catalyst, water, and water-immiscible solvent are combined in a vessel to form a reaction mixture. The total charge of the carbonate precursor is then added to this reaction mixture in the vessel over a total time period of about 15 minutes to about 45 minutes, while the base is co-added to regulate the pH. The carbonate precursor is first added to the reaction mixture along with the base to regulate the pH for a first time period that ranges from about 2 minutes to about 20 minutes. After the first time period ends, the end-capping agent is added in a controlled manner to the reaction mixture, also referred to as programmed addition. The addition of the end-capping agent occurs for a second time period after the first time period, rather than as a bolus at the beginning of the reaction (as in the upfront process). The carbonate precursor and the base are also added concurrently with the end-capping agent during the second time period. After the second time period ends, the remainder of the carbonate precursor continues uninterrupted for a third time period until the total charge is reached. The base is also co-added during the third time period to regulate the reaction pH. The end-capping agent is not added during either the first time period or the third time period. The photoactive additive is thus obtained. The total time period for the reaction is the sum of the first time period, the second time period, and the third time period. In particular embodiments, the second time period in which the solution containing the end-capping agent is added to the reaction mixture begins at a point between 10% to about 40% of the total time period. Put another way, the first time period is 10% of the total time period.

The third process is also referred to as a bis-chloroformate or chloroformate (BCF) process. Chloroformate oligomers are prepared by reacting the carbonate precursor, specifically phosgene, with the dihydroxybenzophenone and the diol chain extender in the absence of the tertiary amine catalyst, while the base is co-added to regulate the pH. The chloroformate oligomers can contain a mixture of monochloroformates, bischloroformates, and bisphenol terminated oligomers. After the chloroformate oligomers are generated, the phosgene can optionally be allowed to substantially condense or hydrolyze, then the end-capping agent is added to the chloroformate mixture. The reaction is allowed to proceed, and the tertiary amine catalyst is added to complete the reaction.

The fourth process uses a tubular reactor. In the tubular reactor, the end-capping agent is pre-reacted with the carbonate precursor (specifically phosgene) to form chloroformates. The water-immiscible solvent is used as a solvent in the tubular reactor. In a separate reactor, the dihydroxybenzophenone, diol chain extender, tertiary amine catalyst, water, and water-immiscible solvent are combined to form a reaction mixture. The chloroformates in the tubular reactor are then fed into the reactor over a first time period along with additional carbonate precursor to complete the reaction while the base is co-added to regulate the pH.

In certain embodiments, a combination of the solution addition and the tubular reactor processes is used. A solution of the polysiloxane monomer is made in a first tank, and a solution of the end-capping agent/monohydroxybenzophenone (when used) is made in a second tank. In a separate reactor, the dihydroxybenzophenone (when used), diol chain extender, tertiary amine catalyst, water, and water-immiscible solvent are combined to form a reaction mixture. The carbonate precursor is first added to the reaction mixture along with the base to regulate the pH for a first time period that ranges from about 2 minutes to about 20 minutes. After the first time period ends, the end-capping agent is added in a controlled manner to the reaction mixture. Concurrently, an amount of the carbonate precursor is charged to the first tank containing the polysiloxane monomer. This forms chloroformates, and the first tank is fed into the reaction mixture as well. The addition of the end-capping agent and the polysiloxane monomer occurs for a second time period after the first time period. The carbonate precursor and the base are also added concurrently during the second time period. After the second time period ends, the end-capping agent and the polysiloxane chloroformates have been added to the reaction mixture. While the addition of the end-capping agent and the polysiloxane chloroformates begin roughly concurrently, they usually do not end concurrently. After the second time period ends, the remainder of the carbonate precursor continues uninterrupted for a third time period until the total charge is reached. The base is also co-added during the third time period to regulate the reaction pH. The end-capping agent and polysiloxane are not added during either the first time period or the third time period. The photoactive additive is thus obtained.

The resulting photoactive additive (e.g. the cross-linkable polycarbonate) contains only a small amount of low-molecular-weight components. This can be measured in two different ways: the level of diarylcarbonates (DAC) and the lows percentage can be measured. Diarylcarbonates are formed by the reaction of two end-capping agents with phosgene, creating a small molecule that contains no dihydroxybenzophenone or diol chain extender (e.g. bisphenol-A). In embodiments, the resulting photoactive additive contains less than 1000 ppm of diarylcarbonates. The lows percentage is the percentage by weight of oligomeric chains having a molecular weight of less than 1000. In embodiments, the lows percentage is 2.0 wt % or less, including from about 1.0 wt % to 2.0 wt %. The DAC level and the lows percentage can be measured by high performance liquid chromatography (HPLC) or gel permeation chromatography (GPC). Also of note is that the resulting photoactive additive does not contain any residual pyridine, because pyridine is not used in the manufacture of the photoactive additive.

Second Polymer Resin

The PAAs can be blended with a polymeric base resin that is different from the photoactive additive, i.e. a second polymer resin, to form the polymeric compositions/blends of the present disclosure. More specifically, the second polymer resin does not contain photoactive groups. The amount of PAA added to the blend can be used to fine-tune the final properties of the article. For example, products requiring high chemical resistance and FR drip inhibition would need increased PAA content. In embodiments, the weight ratio of the photoactive additive to the polymeric base resin is from 1:99 to 99:1, including from about 50:50 to about 85:15, or from about 10:90 to about 15:85, or from about 25:75 to about 50:50. The polymeric base resin has, in specific embodiments, a weight-average molecular weight of about 21,000 or greater, including from about 21,000 to about 40,000. The PAAs are suitable for blending with polycarbonate homopolymers, polycarbonate copolymers, and polycarbonate blends. They are also suitable for blending with polyesters, polyarylates, polyestercarbonates, and polyetherimides.

The blends may be subjected to cross-linking conditions (e.g., UV-radiation) to affect cross-linking of the photoactive additives in the blend. Accordingly, blend compositions of the present disclosure include blends prior to and after cross-linking.

The blends may comprise one or more distinct cross-linkable polycarbonates, as described herein, and/or one or more cross-linked polycarbonates, as described herein, as the photoactive additive. The blends also comprise one or more additional polymers. The blends may comprise additional components, such as one or more additives. In certain embodiments, a blend comprises a cross-linkable and/or cross-linked polycarbonate (Polymer A) and a second polymer (Polymer B), and optionally one or more additives. In another embodiment, a blend comprises a combination of a cross-linkable and/or cross-linked polycarbonate (Polymer A); and a second polycarbonate (Polymer B), wherein the second polycarbonate is different from the first polycarbonate.

In a preferred embodiment, the blend compositions disclosed herein comprise a flame-retardant, a flame retardant additive, and/or an impact modifier. The flame-retardant may be potassium perfluorobutane sulfonate (Rimar salt), potassium diphenyl sulfone-3-sulfonate (KSS), or a combination thereof.

The second polymer (Polymer B) may be any polymer different from the first polymer that is suitable for use in a blend composition. In certain embodiments, the second polymer may be a polyester, a polyestercarbonate, a bisphenol-A homopolycarbonate, a polycarbonate copolymer, a tetrabromo-bisphenol A polycarbonate copolymer, a polysiloxane-co-bisphenol-A polycarbonate, a polyesteramide, a polyimide, a polyetherimide, a polyamideimide, a polyether, a polyethersulfone, a polyepoxide, a polylactide, a polylactic acid (PLA), or any combination thereof.

In certain embodiments, the second polymer may be a vinyl polymer, a rubber-modified graft copolymer, an acrylic polymer, polyacrylonitrile, a polystyrene, a polyolefin, a polyester, a polyesteramide, a polysiloxane, a polyurethane, a polyamide, a polyamideimide, a polysulfone, a polyepoxide, a polyether, a polyimide, a polyetherimide, a polyphenylene ether, a polyphenylene sulfide, a polyether ketone, a polyether ether ketone, an acrylonitrile-butadiene-styrene (ABS) resin, an acrylic-styrene-acrylonitrile (ASA) resin, a polyethersulfone, a polyphenylsulfone, a poly(alkenylaromatic) polymer, a polybutadiene, a polyacetal, a polycarbonate, a polyphenylene ether, an ethylene-vinyl acetate copolymer, a polyvinyl acetate, a liquid crystal polymer, an ethylene-tetrafluoroethylene copolymer, an aromatic polyester, a polyvinyl fluoride, a polyvinylidene fluoride, a polyvinylidene chloride, tetrafluoroethylene, a polylactide, a polylactic acid (PLA), a polycarbonate-polyorganosiloxane block copolymer, or a copolymer comprising: (i) an aromatic ester, (ii) an estercarbonate, and (iii) carbonate repeat units. The blend composition may comprise additional polymers (e.g. a third, fourth, fifth, sixth, etc., polymer).

In certain embodiments, the second polymer may be a homopolycarbonate, a copolycarbonate, a polycarbonate-polysiloxane copolymer, a polyester-polycarbonate, or any combination thereof. In certain embodiments, the second polycarbonate is a p-cumyl phenol capped poly(isophthalate-terephthalate-resorcinol ester)-co-(bisphenol-A carbonate) copolymer. In certain embodiments, the second polycarbonate is a polycarbonate-polysiloxane copolymer.

The p-cumyl phenol capped poly(isophthalate-terephthalate-resorcinol ester)-co-(bisphenol-A carbonate) polymer or a polycarbonate-polysiloxane copolymer may have a polysiloxane content from 0.4 wt % to 25 wt %. In one preferred embodiment, the second polymer is a p-cumylphenol capped poly (19 mol % isophthalate-terephthalate-resorcinol ester)-co-(75 mol % bisphenol-A carbonate)-co-(6 mol % resorcinol carbonate) copolymer (MW=29,000 Daltons). In another preferred embodiment, the second polymer is a p-cumylphenol capped poly(10 wt % isophthalate-terephthalate-resorcinol ester)-co-(87 wt % bisphenol-A carbonate)-co-(3 mol % resorcinol carbonate) copolymer (MW=29,000 Daltons).

In another preferred embodiment, the second polymer is a polycarbonate polysiloxane copolymer. The polycarbonate-polysiloxane copolymer may be a siloxane block co-polycarbonate comprising from about 6 wt % siloxane (±10%) to about 20 wt % siloxane (±10%), and having a siloxane chain length of 10 to 200. In another preferred embodiment, the second polymer is a PC-siloxane copolymer with 20% siloxane segments by weight. In another preferred embodiment, the second polymer is a p-cumylphenol capped poly (65 mol % BPA carbonate)-co-(35 mol % 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP) carbonate) copolymer (MW=25,000 Daltons).

In another preferred embodiment, the second polymer is a polyphosphonate polymer, a polyphosphonate copolymer, or a poly(polyphosphonate)-co-(BPA carbonate) copolymer.

In yet other embodiments, the polymer resin in the blend is selected from the group consisting of a polycarbonate-polysiloxane copolymer; a polycarbonate resin having an aliphatic chain containing at least two carbon atoms as a repeating unit in the polymer backbone; a copolyester polymer; a bisphenol-A homopolycarbonate; a polystyrene polymer; a poly(methyl methacrylate) polymer; a thermoplastic polyester; a polybutylene terephthalate polymer; a methyl methacrylate-butadiene-styrene copolymer; an acrylonitrile-butadiene-styrene copolymer; a dimethyl bisphenol cyclohexane-co-bisphenol-A copolymer; a polyetherimide; a polyethersulfone; and a copolycarbonate of bisphenol-A and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane) (BPTMC).

Other Additives

Other conventional additives can also be added to the polymeric composition (e.g. an impact modifier, UV stabilizer, colorant, flame retardant, heat stabilizer, plasticizer, lubricant, mold release agent, filler, reinforcing agent, antioxidant agent, antistatic agent, blowing agent, or radiation stabilizer).

In preferred embodiments, the blend compositions disclosed herein comprise a flame-retardant, a flame retardant additive, and/or an impact modifier. The flame-retardant may be potassium perfluorobutane sulfonate (Rimar salt), potassium diphenyl sulfone-3-sulfonate (KSS), or a combination thereof.

Various types of flame retardants can be utilized as additives. In one embodiment, the flame retardant additives include, for example, flame retardant salts such as alkali metal salts of perfluorinated C₁-C₁₆ alkyl sulfonates such as potassium perfluorobutane sulfonate (Rimar salt), potassium perfluoroctane sulfonate, tetraethylammonium perfluorohexane sulfonate, potassium diphenylsulfone sulfonate (KSS), and the like, sodium benzene sulfonate, sodium toluene sulfonate (NATS) and the like; and salts formed by reacting for example an alkali metal or alkaline earth metal (for example lithium, sodium, potassium, magnesium, calcium and barium salts) and an inorganic acid complex salt, for example, an oxo-anion, such as alkali metal and alkaline-earth metal salts of carbonic acid, such as Na₂CO₃, K₂CO₃, MgCO₃, CaCO₃, and BaCO₃ or fluoro-anion complex such as Li₃AlF₆, BaSiF₆, KBF₄, K₃AlF₆, KAlF₄, K₂SiF₆, and/or Na₃AlF₆ or the like. Rimar salt and KSS and NATS, alone or in combination with other flame retardants, are particularly useful in the compositions disclosed herein. In certain embodiments, the flame retardant does not contain bromine or chlorine.

The flame retardant optionally is a non-halogen based metal salt, e.g., of a monomeric or polymeric aromatic sulfonate or mixture thereof. The metal salt is, for example, an alkali metal or alkali earth metal salt or mixed metal salt. The metals of these groups include sodium, lithium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, francium and barium. Examples of flame retardants include cesium benzenesulfonate and cesium p-toluenesulfonate. See e.g., U.S. Pat. No. 3,933,734, EP 2103654, and US2010/0069543A1, the disclosures of which are incorporated herein by reference in their entirety.

Another useful class of flame retardant is the class of cyclic siloxanes having the general formula [(R)₂SiO]_(y) wherein R is a monovalent hydrocarbon or fluorinated hydrocarbon having from 1 to 18 carbon atoms and y is a number from 3 to 12. Examples of fluorinated hydrocarbon include, but are not limited to, 3-fluoropropyl, 3,3,3-trifluoropropyl, 5,5,5,4,4,3,3-heptafluoropentyl, fluorophenyl, difluorophenyl and trifluorotolyl. Examples of suitable cyclic siloxanes include, but are not limited to, octamethylcyclotetrasiloxane, 1,2,3,4-tetramethyl-1,2,3,4-tetravinylcyclotetrasiloxane, 1,2,3,4-tetramethyl-1,2,3,4-tetraphenylcyclotetrasiloxane, octaethylcyclotetrasiloxane, octapropylcyclotetrasiloxane, octabutylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, tetradecamethylcycloheptasiloxane, hexadecamethylcyclooctasiloxane, eicosamethylcyclodecasiloxane, octaphenylcyclotetrasiloxane, and the like. A particularly useful cyclic siloxane is octaphenylcyclotetrasiloxane.

Exemplary heat stabilizer additives include, for example, organophosphites such as triphenyl phosphite, tris-(2,6-dimethylphenyl)phosphite, tris-(mixed mono- and di-nonylphenyl)phosphite or the like; phosphonates such as dimethylbenzene phosphonate or the like; phosphates such as trimethyl phosphate, or the like; or combinations comprising at least one of the foregoing heat stabilizers. Heat stabilizers are generally used in amounts of 0.0001 to 1 part by weight, based on 100 parts by weight of the polymer component of the polymeric blend/composition.

Mold release agent (MRA) will allow the material to be removed quickly and effectively. Mold releases can reduce cycle times, defects, and browning of finished product. There is considerable overlap among these types of materials, which may include, for example, phthalic acid esters such as dioctyl-4,5-epoxy-hexahydrophthalate; tris-(octoxycarbonylethyl)isocyanurate; tristearin; di- or polyfunctional aromatic phosphates such as resorcinol tetraphenyl diphosphate (RDP), the bis(diphenyl)phosphate of hydroquinone and the bis(diphenyl)phosphate of bisphenol-A; poly-alpha-olefins; epoxidized soybean oil; silicones, including silicone oils; esters, for example, fatty acid esters such as alkyl stearyl esters, e.g., methyl stearate, stearyl stearate, pentaerythritol tetrastearate (PETS), and the like; combinations of methyl stearate and hydrophilic and hydrophobic nonionic surfactants comprising polyethylene glycol polymers, polypropylene glycol polymers, poly(ethylene glycol-co-propylene glycol) copolymers, or a combination comprising at least one of the foregoing glycol polymers, e.g., methyl stearate and polyethylene-polypropylene glycol copolymer in a suitable solvent; waxes such as beeswax, montan wax, paraffin wax, or the like. Such materials are generally used in amounts of 0.001 to 1 part by weight, specifically 0.01 to 0.75 part by weight, more specifically 0.1 to 0.5 part by weight, based on 100 parts by weight of the polymer component of the polymeric blend/composition.

In particular embodiments, the polymeric blend/composition includes the photoactive additive, an optional polymeric base resin, and a flame retardant which is Rimar salt and which is present in an amount of about 0.05 wt % to about 0.085 wt %, based on the total weight of the composition; and a plaque comprising the polymeric composition has a transparency of 70 to 90% at a thickness of 3.2 mm, measured according to ASTM-D1003-00.

In other particular embodiments, the polymeric blend/composition includes the photoactive additive, an optional polymeric base resin, a flame retardant; a heat stabilizer, and a mold release agent.

The additives, when used, can improve the chemical resistance of the final product. It is contemplated that products can be of any desired shape (e.g. molded article, film, sheet, etc.) and be used in many different applications, for example in the medical, automotive, and consumer electronics fields. Increased chemical resistance may be found against 409 Glass and Surface Cleaner; Alcohol Prep Pad; CaviCide liquid/CaviWipes; CaviWipes; Cidex Plus liquid; Clorox Bleach; Clorox Wipes; Envirocide liquid; For Pro liquid; Gentle dish soap and water; Hydrogen Peroxide Cleaner Disinfectant Wipes; Isopropyl Alcohol wipes; MadaCide-1 liquid; Mar-V-Cide liquid to dilute; Sani-Cloth Bleach Wipes; Sani-Cloth HB Wipes; Sani-Cloth Plus Wipes; Sodium Hypochlorite liquid; Super Sani-Cloth Wipes; Viraguard liquid and Wipes; Virex 256; Windex Blue; Fuel C; Toluene; Heptane; Ethanol; Isopropanol; Windex; Engine oil; WD40; Transmission fluid; Break fluid; Glass wash; Diesel; Gasoline; Banana Boat Sunscreen (SPF 30); Sebum; Ivory Dish Soap; SC Johnson Fantastik Cleaner; French's Yellow Mustard; Coca-Cola; 70% Isopropyl Alcohol; Extra Virgin Olive Oil; Vaseline Intensive Care Hand Lotion; Heinz Ketchup; Kraft Mayonnaise; Chlorox Formula 409 Cleaner; SC Johnson Windex Cleaner with Ammonia; Acetone; Artificial Sweat; Fruits & Passion Cucina Coriander & Olive Hand Cream; Loreal Studioline Megagel Hair Gel; Maybelline Lip Polish; Maybelline Expert Wear Blush—Beach Plum Rouge; Purell Hand Sanitizer; Hot coffee, black; iKlear; Chlorox Wipes; Squalene; Palmitic Acid; Oleic Acid; Palmitoleic Acid; Stearic Acid; and Olive Oil.

Products

Compositions/blends disclosed herein, preferably prior to cross-linking, may be formed, shaped, molded, injection molded, or extruded into a product, particularly thin-walled products, including highly transparent thin-walled products, having improved flame retardance and good physical properties. products

The compositions/blends can be molded into useful shaped products by a variety of means such as injection molding, overmolding, co-injection molding, extrusion, multilayer extrusion, rotational molding, blow molding and thermoforming to form products. The formed products may be subsequently subjected to cross-linking conditions (e.g., UV-radiation) to affect cross-linking of the polycarbonates comprising monohydroxybenzophenone derived endcap. Exemplary products include a film, a sheet, a layer of a multilayer film, or a layer of a multilayer sheet.

Products that may be formed from the compositions/blends include various components for cell phones and cell phone covers, components for computer housings (e.g. mouse covers), fibers, computer housings and business machine housings and parts such as housings and parts for monitors, computer routers, copiers, desk top printers, large office/industrial printers handheld electronic device housings such as computer or business machine housings, housings for hand-held devices, components for light fixtures or home or office appliances, humidifier housings, thermostat control housings air conditioner drain pans, outdoor cabinets, telecom enclosures and infrastructure, Simple Network Intrusion Detection System (SNIDS) devices, network interface devices, smoke detectors, components and devices in plenum spaces, components for medical applications or devices such as medical scanners, X-ray equipment, and ultrasound devices, components for interior or exterior components of an automobile, lenses (auto and non-auto) such as components for film applications, greenhouse components, sun room components, fire helmets, safety shields, safety goggles, glasses with impact resistance, fendors, gas pumps, films for televisions, such as ecofriendly films having no halogen content, solar application materials, glass lamination materials, fibers for glass-filled systems, hand held electronic device enclosures or parts (e.g. walkie-talkie, scanner, media/MP3/MP4 player, radio, GPS system, ebook, tablet), wearable electronic devices (e.g. smart watch, training/tracking device, activity/sleep monitoring system, wristband, or glasses), hand held tool enclosures or parts, smart phone enclosures or parts, turbine blades (e.g., wind turbines), and the like.

In certain embodiments, products that may comprise the composition/blend include automotive bumpers, other automotive, construction and agricultural equipment exterior components, automobile mirror housings, an automobile grille, an automobile pillar, automobile wheel covers, automobile, construction and agricultural equipment instrument panels and trim, construction and agricultural grilles, automobile glove boxes, automobile door hardware and other interior trim, automobile construction and agricultural equipment exterior lights, automobile parts within the engine compartment, plumbing equipment, valves and pumps, air conditioning heating and cooling parts, furnace and heat pump parts, computer parts, electronics parts, projector parts, electronic display parts, copier parts, scanner parts, electronic printer toner cartridges, hair driers, irons, coffee makers, toasters, washing machines, microwaves, ovens, power tools, electric components, lighting parts, dental instruments and equipment, medical instruments, cookware, medical instrument trays, animal cages, fibers, laser welded medical devices, hand held electronic device enclosures or parts (e.g. walkie-talkie, scanner, media/MP3/MP4 player, radio, GPS system, ebook, tablet), wearable electronic devices (e.g. smart watch, training/tracking device, activity/sleep monitoring system, wristband, or glasses), hand held tool enclosures or parts, smart phone enclosures or parts, and fiber optics.

In certain embodiments, products that may comprise the composition/blend include automotive bumpers, other automotive exterior components, automobile mirror housings, an automobile grille, an automobile pillar, automobile wheel covers, automobile instrument panels and trim, automobile glove boxes, automobile door hardware and other interior trim, external automobile trim parts, such as pillars, automobile exterior lights, automobile parts within the engine compartment, an agricultural tractor or device part, a construction equipment vehicle or device part, a construction or agricultural equipment grille, a marine or personal water craft part, an all terrain vehicle or all terrain vehicle part, plumbing equipment, valves and pumps, air conditioning heating and cooling parts, furnace and heat pump parts, computer parts, electronics parts, projector parts, electronic display parts, copier parts, scanner parts, electronic printer toner cartridges, hair driers, irons, coffee makers, toasters, washing machines, microwaves, ovens, power tools, electric components, electric enclosures, lighting parts, dental instruments, medical instruments, medical or dental lighting parts, an aircraft part, a train or rail part, a seating component, sidewalls, ceiling parts, cookware, medical instrument trays, animal cages, fibers, laser welded medical devices, fiber optics, lenses (auto and non-auto), cell phone parts, greenhouse components, sun room components, fire helmets, safety shields, safety glasses, gas pump parts, hand held electronic device enclosures or parts (e.g. walkie-talkie, scanner, media/MP3/MP4 player, radio, GPS system, ebook, tablet), wearable electronic devices (e.g. smart watch, training/tracking device, activity/sleep monitoring system, wristband, or glasses), hand held tool enclosures or parts, smart phone enclosures or parts, and turbine blades.

In certain embodiments, the product is one that requires or must include a material having a UL94 5VA rating performance. Products that require a UL94 5VA rating include, but are not limited to, computer housings, computer housings and business machine housings and parts such as housings and parts for monitors, computer routers, copiers, desk top printers, large office/industrial printers, handheld electronic device housings such as computer or business machine housings, housings for hand-held devices, components for light fixtures including LED fixtures or home or office appliances, humidifier housings, thermostat control housings, air conditioner drain pans, outdoor cabinets, telecom enclosures and infrastructure, Simple Network Intrusion Detection System (SNIDS) devices, network interface devices, smoke detectors, components and devices in plenum spaces, components for medical applications or devices such as medical scanners, X-ray equipment, and ultrasound devices, electrical boxes and enclosures, and electrical connectors.

In certain embodiments, the product is one that requires hydrothermal stability, such as a wind turbine blade, a steam sterilizable medical device, a food service tray, utensils and equipment.

In certain embodiments, the product is one that requires a combination of transparency, flame resistance, and/or impact resistance. For example, in certain embodiments the product may be a safety shield, safety goggles, a gas/fuel pump housing, a display window or part, or the like.

Ultraviolet Irradiation

The photoactive additive (PAA) can be blended with one or more polymeric base resins by melt blending or solution blending to form a polymeric composition/blend. The PAA-containing blend can be then be formed into a product by a variety of known processes such as solution casting, profile extrusion, film and/or sheet extrusion, sheet-foam extrusion, injection molding, blow molding, thermoforming, and the like. The product is then exposed to ultraviolet (UV) light at an appropriate wavelength and in an appropriate dosage that brings about the desired amount of crosslinking for the given application. Depending on the end use application and the desired properties, the UV exposure can be performed on one or more surfaces of the product.

The product where the enhanced properties are needed should be exposed with a substantially uniform dose of UV light. The exposure can be accomplished using standard methods known in the art. For example, the UV light can come from any source of UV light such as, but not limited to, those lamps powered by microwave, HID lamps, and mercury vapor lamps. In some other embodiments, the product is exposed by using natural sunlight. The exposure time will be dependent on the application and color of material. It can range from a few minutes to several days. Alternatively, the crosslinking can be accomplished by using a UV-emitting light source such as a mercury vapor, High-Intensity Discharge (HID), or various UV lamps. For example, commercial UV lamps are sold for UV curing from manufacturers such as Hereaus Noblelight and Fusion UV. Non-limiting examples of UV-emitting light bulbs include mercury bulbs (H bulbs), or metal halide doped mercury bulbs (D bulbs, H+ bulbs, and V bulbs). Other combinations of metal halides to create a UV light source are also contemplated. Exemplary bulbs could also be produced by assembling the lamp out of UV-absorbing materials and considered as a filtered UV source. A mercury arc lamp is not used for irradiation. An H bulb has strong output in the range of 200 nm to 320 nm. The D bulb has strong output in the 320 nm to 400 nm range. The V bulb has strong output in the 400 nm to 420 nm range.

It may also be advantageous to use a UV light source where the harmful wavelengths (those that cause polymer degradation or excessive yellowing) are removed or not present. Equipment suppliers such as Heraeus Noblelight and Fusion UV provide lamps with various spectral distributions. The light can also be filtered to remove harmful or unwanted wavelengths of light. This can be done with optical filters that are used to selectively transmit or reject a wavelength or range of wavelengths. These filters are commercially available from a variety of companies such as Edmund Optics or Praezisions Glas & Optik GmbH. Bandpass filters are designed to transmit a portion of the spectrum, while rejecting all other wavelengths. Longpass edge filters are designed to transmit wavelengths greater than the cut-on wavelength of the filter. Shortpass edge filters are used to transmit wavelengths shorter than the cut-off wavelength of the filter. Various types of materials, such as borosilicate glass, can be used as a long pass filter. Schott and/or Praezisions Glas & Optik GmbH for example have the following long pass filters: WG225, WG280, WG295, WG305, WG320 which have cut-on wavelengths of ˜225, 280, 295, 305, and 320 nm, respectively. These filters can be used to screen out the harmful short wavelengths while transmitting the appropriate wavelengths for the crosslinking reaction.

UV wavelengths can be separated into four different categories. UVA refers to wavelengths from 320 nm to 390 nm. UVB refers to wavelengths from 280 nm to 320 nm. UVC refers to wavelengths from 250 nm to 260 nm. UW refers to wavelengths from 395 nm to 445 nm. These wavelengths of light were measured with an EIT PowerPuck, and the categories are defined by the manufacturer (EIT Inc., Sterling, Va.).

The exposed product will have a cross-linked outer surface and an inner surface that is either lightly cross-linked or not cross-linked. The outer surface can be cross-linked to such a degree that the outer surface is substantially insoluble in the common solvents for the starting resins. The percentage of the insolubles (insoluble component) will be dependent on the part geometry and surface-to-volume ratio.

The following examples are provided to illustrate the polymers, compositions/blends, products, processes, and properties of the present disclosure. The examples are merely illustrative and are not intended to limit the disclosure to the materials, conditions, or process parameters set forth therein.

EXAMPLES

All solvents and reagents used were analytical grade.

Molecular weight determinations were performed using gel permeation chromatography (GPC), using a cross-linked styrene-divinylbenzene column and calibrated to polycarbonate references using a UV-VIS detector set at 264 nm. Samples were prepared at a concentration of about 1 mg/ml, and eluted at a flow rate of about 1.0 ml/min.

The presence of chloroformate was determined by placing approximately 1 mL of reactor organic phase onto paper tape that is impregnated with 4-(4-nitrobenzyl)pyridine. A yellow-to-orange color change indicated the presence of chloroformate groups.

The presence of unreacted bisphenol-A (BPA) in reactor samples was determined by the following method. 2 mL of reactor sample organic phase was diluted in 5 mL dichloromethane. To the solution was added 5 mL dilute ammonium hydroxide and the mixture shaken vigorously for 30 seconds. To the mixture was added 10 mL of 1% aqueous potassium ferricyanide and the mixture shaken vigorously for 30 seconds. To the mixture was added 5 mL of 1% aqueous 4-aminoantipyrine and the mixture shaken vigorously for 30 seconds. A yellow color indicated an acceptable low amount of residual BPA. An orange to red color indicated an unacceptable high amount of residual BPA.

(A) Preparation of Cross-Linkable Polycarbonate-Polysiloxane Copolymer

Sample A10 was used to make a terpolymer containing 5.3 mole % 4,4′-dihydroxybenzophenone (4,4′-DHBP), dimethylsiloxane monomer, remainder bisphenol-A (BPA), using p-cumylphenol (PCP) as an end-capping agent. The dimethylsiloxane monomer had the structure of Formula (II-a) above, where D is between 10 and 75. Generally, the polysiloxane monomer was pre-reacted in a tube process, then added directly to a batch containing the DHBP, BPA, and PCP.

A solution of p-cumylphenol (168 grams, 0.79 moles, 4.3 mole %) was prepared in 500 mL of dichloromethane. The p-cumylphenol (PCP) solution was placed in an addition pot connected to the reactor via a dosing pump.

A solution of eugenol capped D45 siloxane (312 grams, 0.0082 mole, 5.7 wt % siloxane) was prepared in 900 mL of dichloromethane. The D45 siloxane solution was placed in an addition tank connected to the tubular reactor via a dosing pump. The tubular reactor (½ inch diameter×15 feet length, spiral upflow) is connected to the batch reactor.

To the formulation tank was added dichloromethane (13 L), DI water (10 L), 4,4′-dihydroxybenzophenone (200 grams, 0.93 moles, 5.3 mole %), bisphenol-A (3800 grams, 16.6 moles), triethylamine (52 grams, 0.37 moles) and sodium gluconate (10 grams, iron scavenger). The mixture was stirred for 5 minutes, then transferred to the 70 L batch reactor which was equipped with an overhead condenser, circulation loop, pH probe and various material addition nozzles. The formulation tank was rinsed with dichloromethane (5 L) which was transferred to the batch reactor. The reactor agitator was started and the circulation flow was set at 80 L/min. Phosgene vapor flow to the reactor was initiated (80 g/min flow rate) by the DCS and an initial amount (220 grams, 2.2 moles) was added. The pH of the reaction was maintained at a target of 10.0 by DCS-controlled addition of 33% aqueous NaOH.

After addition of the initial amount of phosgene, the PCP solution was added to the reactor at 500 mL/min flow rate by DCS control while phosgene flow to the reactor continued. At the same time the feed to the tubular reactor was initiated with D45 siloxane flow (500 g/min) combining with phosgene (28 g/min, 0.28 mole/min) and 18% aqueous NaOH (316 g/min, 1.4 moles/min) in the plug flow reactor directly feeding into the batch reactor. The tubular reactor was flushed with dichloromethane (2 L). Phosgene addition continued with pH control throughout the additions and until the total set point was reached (2200 grams, 22.2 moles). After completion of the phosgene addition, a sample of the reactor was obtained and verified to be free of un-reacted BPA and free of chloroformate. Mw of a reaction sample was determined by GPC using a UV detector (Mw=22690, PDI=2.4). An additional charge of phosgene was added (200 grams, 2.0 mole) to the reactor. The reactor was purged with nitrogen then the batch was transferred to the centrifuge feed tank.

To the batch in the centrifuge feed tank was added dilution dichloromethane (8 L) then the mixture was purified using a train of liquid-liquid centrifuges. Centrifuge one separated the brine phase. Centrifuge two removed the triethylamine catalyst by extracting the resin solution with aqueous hydrochloric acid (pH 1). Centrifuges three through eight removed residual ions by extracting the resin solution with DI water. A sample of the resin solution was tested and verified less than 5 ppm each of ionic chloride and residual triethylamine.

The resin solution was transferred to the precipitation feed tank. The resin was isolated as a white powder by steam precipitation followed by drying in a cone shaped vessel using heated nitrogen (210 F). Powder yield 3674 grams. Mw=22460 PDI=2.4.

A sample of the dried polymer resin was hot pressed at 515° F. to give a film of 295 microns thickness. The film was irradiated using UV light (36 J/cm² UVA, no detectable UVC). The thickness after irradiation was 285 microns. The film was submerged in dichloromethane to dissolve the non-crosslinked polymer. The remaining gel was dried. The thickness of the dried gel layer was 49 microns. To another similarly prepared and irradiated film was placed several drops of acetone. After the acetone evaporated from the irradiated film, no difference was observed between the acetone-tested film and a control film.

The properties of Sample A10 are shown in Table 1 below:

TABLE 1 Sample mol % Mol % Mw PDI Lows % ID Process endcap DHBP UV UV UV A10 siloxane tubular 4.3 5.3 22460 2.4 1.29 reaction, endcap program addition

The present disclosure has been described with reference to exemplary embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the present disclosure be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. 

The invention claimed is:
 1. A photoactive additive that is a cross-linkable polycarbonate terpolymer formed from a reaction comprising: a dihydroxybenzophenone; a first linker moiety comprising a plurality of functional groups, wherein each functional group reacts with the hydroxyl groups of the dihydroxybenzophenone; a diol chain extender; an end-capping agent; and a polysiloxane monomer in an amount such that the additive contains from 1 wt % to 25 wt % of siloxane, based on the total weight of the polycarbonate terpolymer.
 2. The additive of claim 1, wherein the dihydroxybenzophenone is 4,4′-dihydroxybenzophenone; the diol chain extender is bisphenol-A; and the first linker moiety is phosgene.
 3. The additive of claim 1, containing from about 0.5 mole % to about 50 mole % of the dihydroxybenzophenone.
 4. The additive of claim 1, containing from about 1 wt % to about 25 wt % of the dihydroxybenzophenone.
 5. The additive of claim 1, wherein the end-capping agent is selected from the group consisting of phenol, p-t-butylphenol, p-cumylphenol, octylphenol, p-cyanophenol, and a monohydroxybenzophenone.
 6. The additive of claim 1, wherein the polysiloxane monomer has the structure of one of the following Formulas (I)-(III):

wherein each Ar is independently aryl; each R is independently alkyl, alkoxy, alkenyl, alkenyloxy, aryl, aryloxy, arylalkyl, or alkylaryl; each R₆ is independently C₁-C₃₀ alkyl, C₁-C₃₀ aryl, or C₁-C₃₀ alkylaryl; each M is independently cyano, nitro, alkyl, alkoxy, alkenyl, alkenyloxy, aryl, aryloxy, arylalkyl, or alkylaryl; each n is independently an integer from 0 to 4; each R₂ is independently an aliphatic group; and D and E are an average value of 2 to about
 1000. 7. The additive of claim 1, wherein the diol chain extender has the structure of one of the following Formulas (A)-(G):

wherein R^(a) and R^(b) each represent a halogen atom or a monovalent hydrocarbon group and may be the same or different; p and q are each independently integers of 0 to 4; and A represents one of the groups of formula (A-1):

wherein R^(c) and R^(d) each independently represent a hydrogen atom or a monovalent linear or cyclic hydrocarbon group and R^(e) is a divalent hydrocarbon group;

wherein each R^(k) is independently a C₁₋₁₀ hydrocarbon group, and n is 0 to 4;

wherein each X is independently hydrogen, halogen, or alkyl; and j is an integer from 1 to 20;

wherein R¹³ and R¹⁵ are each independently a halogen or a C₁-C₆ alkyl group, R¹⁴ is a C₁-C₆ alkyl, phenyl, or phenyl substituted with up to five halogens or C₁-C₆ alkyl groups, and c is 0 to 4;

wherein R₁ represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aryl-substituted alkenyl group having 7 to 13 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; R₂ represents a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aryl-substituted alkenyl group having 7 to 13 carbon atoms, or a fluoroalkyl group having 1 to 12 carbon atoms; m represents an integer of 0 to 4; and n represents an integer of 0 to 14;

wherein R₁ to R₄ are each independently a hydrogen atom, a hydrocarbon group with 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom; or

wherein R₁ is an isosorbide unit and R₂-R₉ are each independently a hydrogen, a halogen, a C₁-C₆ alkyl, a methoxy, an ethoxy, or an alkyl ester.
 8. The additive of claim 1, wherein the first linker moiety has the structure of one of the following Formulas (30), (32), or (33):

where Y is hydroxyl, halogen, alkoxy, or aryloxy; and where n is 1 to
 20. 9. The additive of claim 1, wherein the molar ratio of the dihydroxybenzophenone to the first linker moiety is from 1:2 to 1:200.
 10. The additive of claim 1, wherein the reaction that forms the photoactive additive further comprises a secondary linker moiety having at least three functional groups, each of which can react with a functional group of the first linker moiety.
 11. The additive of claim 10, wherein the secondary linker moiety has the structure of one of the following Formulas (43)-(48):


12. The additive of claim 1, having a weight average molecular weight of 15,000 or greater.
 13. The additive of claim 1, wherein the cross-linkable polycarbonate terpolymer has a weight-average molecular weight from 17,000 to 80,000 Daltons, as measured by gel permeation chromatography using a UV-VIS detector and polycarbonate standards.
 14. The additive of claim 1, wherein a molded part formed from the cross-linkable polycarbonate terpolymer exhibits 100% ductility at minus 20° C. at 3.2 mm thickness in a notched Izod test according to ASTM D256.
 15. A product formed from a composition comprising the photoactive additive of claim
 1. 16. The product of claim 15, wherein the product is at least one of an automotive bumper, an automotive exterior component, an automobile mirror housing, an automobile grille, an automobile pillar, an automobile wheel cover, an automobile instrument panel or trim, an automobile glove box, an automobile door hardware or other interior trim, an automobile exterior light, an automobile part within the engine compartment, an agricultural tractor or device part, a construction equipment vehicle or device part, a construction or agricultural equipment grille, a marine or personal water craft part, an all terrain vehicle or all terrain vehicle part, plumbing equipment, a valve or pump, an air conditioning heating or cooling part, a furnace or heat pump part, a computer part, a computer router, a desk top printer, a large office/industrial printer, an electronics part, a projector part, an electronic display part, a copier part, a scanner part, an electronic printer toner cartridge, a hair drier, an iron, a coffee maker, a toaster, a washing machine or washing machine part, a microwave, an oven, a power tool, an electric component, an electric enclosure, a lighting part, a dental instrument, a medical instrument, a medical or dental lighting part, an aircraft part, a train or rail part, a seating component, a sidewall, a ceiling part, cookware, a medical instrument tray, an animal cage, fibers, a laser welded medical device, fiber optics, a lense (auto and non-auto), a cell phone part, a greenhouse component, a sun room component, a fire helmet, a safety shield, safety glasses, a gas pump part, a humidifier housing, a thermostat control housing, an air conditioner drain pan, an outdoor cabinet, a telecom enclosure or infrastructure, a Simple Network Detection System (SNIDS) device, a network interface device, a smoke detector, a component or device in a plenum space, a medical scanner, X-ray equipment, a construction or agricultural equipment, a hand held electronic device enclosure or part, a wearable electronic device, a hand held tool enclosure or part, a smart phone enclosure or part, and a turbine blade.
 17. The product of claim 15, wherein the product is a molded article, a film, a sheet, a layer of a multilayer film, or a layer of a multilayer sheet.
 18. The product of claim 15, wherein the product is formed by injection molding, overmolding, co-injection molding, extrusion, multilayer extrusion, rotational molding, blow molding, or thermoforming.
 19. The product of claim 15, wherein the product is exposed to UV radiation to cause crosslinking of the photoactive additive.
 20. A blend comprising the additive of claim 1 and a polymeric base resin that is different from the photoactive additive.
 21. A process for making a photoactive additive from a dihydroxybenzophenone, a diol chain extender, a polysiloxane monomer, an end-capping agent, a carbonate precursor, a base, a tertiary amine catalyst, water, and a water-immiscible organic solvent, comprising: pre-reacting the polysiloxane monomer with the carbonate precursor in a tubular reactor to form chloroformates; combining the dihydroxybenzophenone, diol chain extender, tertiary amine catalyst, water, and water-immiscible solvent to form a reaction mixture; adding the carbonate precursor to the reaction mixture over a first time period while co-adding the base to regulate the reaction pH; adding the end-capping agent and the chloroformates to the reaction mixture for a second time period while continuing to add the carbonate precursor and the base; and continuing to add the carbonate precursor and the base to the reaction mixture for a third time period after the second time period is complete to obtain the photoactive additive; wherein the polysiloxane monomer is present in an amount such that the additive contains from 1 wt % to 25 wt % of siloxane, based on the total weight of the polycarbonate resin.
 22. The process of claim 21, wherein the carbonate precursor is phosgene, the diol chain extender is bisphenol-A, the base is an alkali metal hydroxide, and the water-immiscible organic solvent is methylene chloride.
 23. The process of claim 21, wherein the end-capping agent is dissolved in a solvent prior to being added to the reaction mixture, the solvent being either the water-immiscible organic solvent or water containing a base.
 24. The process of claim 23, wherein the end-capping agent is dissolved in a dilute aqueous sodium hydroxide solution.
 25. The process of claim 24, wherein the solution contains from about 1 to about 2 moles of NaOH per mole of the end-capping agent, and contains from about 5 wt % to about 20 wt % of the end-capping agent compound.
 26. The process of claim 21, wherein the reaction pH is regulated to remain between about 8.5 and about
 10. 27. A cross-linkable polycarbonate terpolymer formed from a reaction comprising a dihydroxybenzophenone, a diol chain extender, and a polysiloxane monomer in an amount such that the terpolymer contains from 1 wt % to 25 wt % of siloxane, based on the total weight of the terpolymer, wherein the terpolymer is formed by: pre-reacting the polysiloxane monomer with a carbonate precursor in a tubular reactor to form chloroformates; combining the dihydroxybenzophenone, the diol chain extender, a tertiary amine catalyst, water, and a water-immiscible solvent to form a reaction mixture; adding the carbonate precursor to the reaction mixture over a first time period while co-adding the base to regulate the reaction pH; adding the chloroformates to the reaction mixture for a second time period while continuing to add the carbonate precursor and the base; and continuing to add the carbonate precursor and the base to the reaction mixture for a third time period after the second time period is complete to obtain the terpolymer.
 28. A crosslinked layer formed from a polymeric blend that has been exposed to UV radiation, the blend comprising: a photoactive additive that is a cross-linkable polycarbonate terpolymer formed from a reaction comprising a dihydroxybenzophenone, a diol chain extender, and a polysiloxane monomer in an amount such that the terpolymer contains from 1 wt % to 25 wt % of siloxane, based on the total weight of the terpolymer; and a polymer resin which is different from the photoactive additive.
 29. The layer of claim 28, wherein the crosslinked layer contains chains from both the photoactive additive and the polymer resin.
 30. The layer of claim 28, wherein the crosslinking is sufficient to create a continuous insoluble layer containing both the photoactive additive and the polymer resin. 